Prepare v3.15.1

Prepare v3.15.1

Add support for logging all DAP request/responses behind a flag

Log Flutter initialization to main log file

Fixes Dart-Code#2856.

Record when debug adapter starts / errors

Add temporary workaround for Theia

See eclipse-theia/theia#7690.

Support running Flutter apps without a VM Service connection

Fixes Dart-Code#2842.

Prepare v3.15.0

Final(!) eslint fixes

Include argv in debug adapter error message

See Dart-Code#2782.